2.  10, 5, 13, 10, 16, 20, 19, (….)  
Answer: Option B Explanation: There are two series (10, 13, 16, 19) and (5, 10, 20, 40), one increasing by 3 and the other multiplied by 2.

3.  1, 4, 9, 16, 25, 36, 49, (….)  
Answer: Option C Explanation: Numbers are 1^{2}, 2^{2}, 3^{2}, 4^{2}, 5^{2}, 6^{2}, 7^{2}. So, the next number is 8^{2} = 64. 
4.  2, 4, 12, 48, 240, (….)  
Answer: Option B Explanation: Go on multiplying the given numbers by 2, 3, 4, 5, 6. So, the correct next number is 1440. 
5.  8, 7, 11, 12, 14, 17, 17, 22, (….)  
Answer: Option B Explanation: There are two series (8, 11, 14, 17, 20) and (7, 12, 17, 22) increasing by 3 and 5 respectively. 
6.  11, 13, 17, 19, 23, 29, 31, 37, 41, (….)  
Answer: Option A Explanation: Numbers are all primes. The next prime is 43.

7.  8, 24, 12, 36, 18, 54, (….)  
Answer: Option A Explanation: Numbers are alternatively multiplied by 3 and divided by 2. So, the next number = 54 ÷ 2 = 27. 
8.  2, 6, 12, 20, 30, 42, 56, (….)  
Answer: Option C Explanation: The pattern is 1 x 2, 2 x 3, 3 x 4, 4 x 5, 5 x 6, 6 x 7, 7 x 8. So, the next number is 8 x 9 = 72. 
9.  4, 8, 16, 32, 64, (….)  
Answer: Option B Explanation: Each number is the proceeding number multiplied by 2. So, the required number is 128. 
10.  7, 26, 63, 124, 215, 342, (….)  
Answer: Option B Explanation: Numbers are (2^{3} – 1), (3^{3} – 1), (4^{3} – 1), (5^{3} – 1), (6^{3} – 1), (7^{3} – 1) etc. So, the next number is (8^{3} – 1) = (512 – 1) = 511. 
11.  5, 10, 13, 26, 29, 58, 61, (….)  
Answer: Option A Explanation: Numbers are alternatively multiplied by 2 and increased by 3. So, the missing number = 61 x 2 = 122. 
12.  15, 31, 63, 127, 255, (….)  
Answer: Option B Explanation: Each number is double the preceding one plus 1. So, the next number is (255 x 2) + 1 = 511. 